What makes a great photographer

As a photographer, I am always looking at other photographers work and comparing my images to others. I'm sure many other photographers do the same. Things that cross our minds are; how did he/she get that shot? How did they discover a particular location? What equipment did they use and what were their camera settings? How much of the final image is reality and how much of the final image is the result of post processing? Ultimately, what differentiates one photographers work from another.

What makes a great photographer? Great images with great subjects? Public appeal? I guess all the above. It doesn't matter how much you like your own work. If nobody is buying your work, that generally means that nobody wants to have your images on their wall or representing their products in advertising.